Catalysts for preparation of ultra high molecular weight polyethylene (UHMWPE) and process for preparation thereof

Abstract

The present invention relates to novel polymerization catalysts. More particularly, the present invention relates to a novel catalysts for the preparation of ultra high molecular weight polyethylene (UHMWPE) and process for preparation thereof. The present invention further relates to a process for the preparation of disentangled ultra high molecular weight polyethylene (dis-UHM-WPE).

The invention claimed is: 
     
       1. An olefin polymerization catalyst comprising a metal complex of Formula (I) 
       
         
           
           
               
               
           
         
       
       wherein
 M is a transition metal atom of Group 3 to Group 11 of the periodic table; 
 A is sulfonate (SO 3 ) or carboxylate (CO 2 ); 
 when n=0, D=N═CH—or when n=1, D=N; 
 X=Cl, Br, I, BF 4 , or OAc; and 
 R, and R 1  to R 4  are the same or different, and are each a hydrogen atom, a halogen atom, a hydrocarbon group, a heterocyclic group, an oxygen-containing group, a nitrogen-containing group, a boron-containing group, a sulfur-containing group, a phosphorus-containing group, a silicon-containing group, a germanium-containing group or a tin-containing group, and two or more of them may be bonded to each other to form a ring. 
 
     
     
       2. The olefin polymerization catalyst as claimed in  claim 1 , wherein said transition metal is selected from the group consisting of titanium, zirconium, hafnium, vanadium, ytterbium and niobium. 
     
     
       3. The olefin polymerization catalyst as claimed in  claim 1 , wherein said metal complex of Formula (I) is Bis[2-(((2,3,4,5,6-pentaflourophenyl)imino)methyl)benzenesulfonato]titanium(IV) Dichloride or Bis[2-(((4-methoxybenzylidene)amino)benzoate]Ti(IV) Dichloride. 
     
     
       4. A process for the preparation of the catalyst as claimed in  claim 1  comprising the steps of:
 (a) stirring the reaction mixture of a sodium salt of an aldehyde and an amine in a suitable solvent in presence of an alkyl/aryl sulfonic acid followed by refluxing the reaction mixture at a temperature ranging from 140 to 160° C. for the period ranging from 4 to 6 hours to obtain an imine compound; and 
 (b) adding an organic solvent solution of a metal halide to a stirred solution of the imine compound of step (a) in a suitable solvent at the temperature ranging from −78° C. to 80° C. followed by stirring the reaction mixture for the time period ranging from 18 to 20 hours at the temperature ranging from 25° C. to 40° C. to obtain the metal complex of Formula (I) wherein A is sulfonate group. 
 
     
     
       5. The process as claimed in  claim 4 , wherein said sodium salt of an aldehyde is a sodium salt of 2-formylbenzenesulfonic acid, sodium 2-formyl-6-methylbenzenesulfonate, or sodium 2-(tert-butyl)-6-formylbenzenesulfonate. 
     
     
       6. The process as claimed in  claim 4 , wherein said amine is aliphatic or aromatic. 
     
     
       7. The process as claimed in  claim 4 , wherein said solvent of step (a) is dimethyl formamide, dimethyl sulfoxide, methanol, acetonitrile, or benzonitrile. 
     
     
       8. The process as claimed in  claim 4 , wherein said alkyl/aryl sulfonic acid is p toluenesulfonic acid, methane sulfonic acid, or trifluromethane sulfonic acid. 
     
     
       9. The process as claimed in  claim 4 , wherein said organic solvent of step (b) is toluene, heptane, decane, or xylene. 
     
     
       10. The process as claimed in  claim 4 , wherein said metal halide is titanium tetrachloride, zirconium tetrachloride, titanium tetrabromide, or zirconium tetrabromide. 
     
     
       11. The process as claimed in  claim 4 , wherein said solvent of step (b) is dimethyl formamide, dimethyl sulfoxide, toluene, diethyl ether, or dioxane. 
     
     
       12. A process for the preparation of the catalyst as claimed in  claim 1  comprising the steps of:
 (a) stirring the reaction mixture of an aldehyde and an amine in a suitable solvent in presence of an alkylsulfonic acid followed by refluxing the reaction mixture at temperature ranging from 65 to 70° C. for the period ranging from 4 to 6 hours to obtain an amino compound; 
 (b) adding an alkyllithium/ n-hexane solution to a stirred solution of step (a) in a solvent at the temperature ranging from −78° C. to −80° C. followed by stirring the reaction mixture for the time period ranging from 3 to 4 hours at the temperature ranging from 25° C. to 40° C.; and 
 (c) adding a solution of a metal halide in an organic solvent to a solution of step (b) at the temperature ranging from −78° C. to 80° C. followed by stirring the reaction mixture for the time period ranging from 18 to 20 hours at the temperature ranging from 25° C. to 40° C. to obtain the metal complex of Formula (I) wherein A is carboxylate group. 
 
     
     
       13. The process as claimed in  claim 12 , wherein said amine is 2-amino-6-methylbenzoic acid, anthranilic acid, or 2-amino-6-tert-butylbenzoic acid. 
     
     
       14. The process as claimed in  claim 12 , wherein said aldehyde is 2,3,4,5,6-pentafluorobenzaldehyde, 2,6-difluorobenzaldehyde, anisaldehyde, or benzaldehyde. 
     
     
       15. The process as claimed in  claim 12 , wherein said solvent of step (a) is a polar solvent. 
     
     
       16. The process as claimed in  claim 12 , wherein said solvent of step (b) is tetrahydrofuran, toluene, diethyl ether, or dioxane. 
     
     
       17. The process as claimed in  claim 12 , wherein said organic solvent is toluene, xylene, hexane, or heptane. 
     
     
       18. The process as claimed in  claim 12 , wherein said metal halide is titanium tetrachloride, zirconium tetrachloride, titanium tetrabromide, or zirconium tetrabromide. 
     
     
       19. A process for the preparation of a disentangled ultra high molecular weight polyethylene using said polymerization catalyst as claimed in  claim 1  in the presence of a co-catalyst comprising the steps of:
 (a) mixing the co-catalyst in a solvent followed by pressurizing the ethylene gas in reaction vessel; and 
 (b) polymerizing ethylene by dissolving the polymerization catalyst in a solvent at the temperature ranging from 0 to 45° C. 
 
     
     
       20. The process as claimed in  claim 19 , wherein said co-catalyst is selected from the group consisting of methylaluminoxane (MAO) and trialkylaluminium. 
     
     
       21. The process as claimed in  claim 19 , wherein said solvent of step (b) is a hydrocarbon. 
     
     
       22. The process as claimed in  claim 19 , wherein said polymerization temperature for preparation of the disentangled ultra high molecular weight polyethylene is ranging from 0 to 45° C. 
     
     
       23. The process as claimed in  claim 19 , wherein said polymerization reaction is carried out in continuous or batch mode. 
     
     
       24. The process as claimed in  claim 19 , wherein said polymerization is carried out under a pressure of 1 to 10 bars. 
     
     
       25. The process as claimed in  claim 19 , wherein the concentration of said polymerization catalyst is in the range of 1 to 10 μmol. 
     
     
       26. The process as claimed in  claim 19 , wherein said co-catalyst comprise a scavenger. 
     
     
       27. The process as claimed in  claim 19 , wherein the average molecular weight of said disentangled ultra high molecular weight polyethylene is ranging from 1 to 10 million g/mol. 
     
     
       28. The olefin polymerization catalyst as claimed in  claim 1 , wherein R 1  is an aromatic group, or mono, di, tri, tetra, penta substituted phenyl, in which one or more or all five substituent is F, Cl, Br, or I. 
     
     
       29. The process as claimed in  claim 4 , wherein said amine is an aromatic amine. 
     
     
       30. The process as claimed in  claim 4 , wherein said amine is 2,3,4,5,6-pentafluoroaniline. 
     
     
       31. The process as claimed in  claim 4 , wherein said aldehyde is 2,6-difluorobenzaldehyde, anisaldehyde, or benzaldehyde. 
     
     
       32. The process as claimed in  claim 12 , wherein said solvent of step (a) is an alcohol. 
     
     
       33. The process as claimed in  claim 12 , wherein said solvent of step (a) is methanol, ethanol, or propanol. 
     
     
       34. The process as claimed in  claim 19 , wherein said solvent of step (b) is a saturated hydrocarbon. 
     
     
       35. The process as claimed in  claim 19 , wherein said solvent of step (b) is toluene, xylene, heptane, or decane. 
     
     
       36. The process as claimed in  claim 19 , wherein said polymerization temperature for preparation of disentangled ultra high molecular weight polyethylene is ranging from 35 to 40° C. 
     
     
       37. The process as claimed in  claim 26 , wherein said scavenger is triethylaluminium, triisobutylaluminum, tris-n-octylaluminium, tetraisobutyl-dialuminoxane, diethyl zinc, tris-n-hexyl aluminum or diethylchloro aluminum.